A theory of physics explains the fragmentation of tropical forests

Tropical forests around the world play a key role in the global carbon cycle and harbour more than half of the species worldwide. However, increases in land use in recent decades caused unprecedented losses of tropical forest. Scientists at the Helmholtz Centre for Environmental Research (UFZ) have adapted a method from physics to describe the fragmentation of tropical forests mathematically. In the scientific journal Nature, they explain how this allows them to model and understand the fragmentation of forests on a global scale. They found that forest fragmentation on all three continents is close to a critical point beyond which the fragment number will strongly increase. This will have severe consequences for biodiversity and carbon storage.

In order to analyse global patterns of forest fragmentation, a UFZ research group led by Prof. Andreas Huth used remote sensing data quantifying forest cover in the tropics in an extremely high resolution of 30 meters, resulting in more than 130 million forest fragments. To their surprise, they found that the fragment sizes on all three continents have similar frequency distributions. For example, the number of forest fragments smaller than 10,000 hectares is similar in all three regions—11.2 percent in Central and South America, 9.9 percent in Africa and 9.2 percent in Southeast Asia. "This is surprising, because land use noticeably differs from continent to continent," says Dr. Franziska Taubert, mathematician in Huth's team and first author of the study. For instance, very large forest areas are transformed into agricultural land in the Amazon region. By contrast, in the forests of Southeast Asia, economically attractive tree species are often taken from the forest.

Explanations - Fragmentation - Patterns - UFZ - Modelers

When searching for explanations for the identical fragmentation patterns, the UFZ modelers found their answer in physics. "The fragment size distribution follows a power law with almost identical exponents on all three continents,"...